Flow controller

ABSTRACT

A flow controller is provided for delivering a precise volume of fluid such as high purity fluid streams to a processing destination, such as a wafer processing chamber. The flow controller includes a base with a seamless slot formed in a face thereof, providing a predictable pressure drop. The seamless slot is in fluidic communication with a sensor channel extending downwardly from the seamless slot first having temperature sensors thereon for inferring the mass flow through the flow controller. A valve is in fluidic communication with the seamless slot and is operably connected to the temperature sensors such that the valve opening is adjusted until the mass flow inferred by the temperature sensors is equal to a desired mass flow.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the priority date of ProvisionalU.S. Patent Application Ser. No. 60/271,947 filed Feb. 28, 2001 forsubject matter disclosed therein.

FIELD OF THE INVENTION

The present invention relates, in general, to a fluid delivery system.More particularly, this invention provides an integrated fluid deliverysystem (IFDS) for providing high purity fluid streams, such as for awafer processing chamber.

BACKGROUND OF THE INVENTION

High purity fluid delivery systems are employed in demandingmanufacturing environments such as the semiconductor manufacturingindustry. The delivery systems are designed to precisely dispense fluidswhich may be hazardous in nature (i.e., corrosive, poisonous) and/orexpensive. For example, in semiconductor processing/manufacturing,various stages such as low pressure chemical vapor deposition (LPCVD),oxidation, and plasma enhanced chemical vapor deposition (PECVD),require corrosive precursors such as boron, silicon and phosphorous tobe delivered to a wafer processing chamber for the manufacture ofsemiconductor devices.

Typically, high purity fluid systems in the semiconductor manufacturingindustry employ a complex network of tubing (plumbing) that require highintegrity welds between tube sections and conduit assemblies forchanneling the fluids to a variety of fluid control, metering, andoperational devices. As the layout of each system is dependent upon thenumber and location of the control, metering and operational devices,the “system schematic” is equal in complexity to the number of highintegrity welds and corresponding conduit arrangement.

As can be appreciated, the number of high cost conduit assembly (i.e.,valving) and high integrity welding connections, as well as theincreased complexity of the corresponding system schematic leads toliquid delivery systems which are costly to both maintain andmanufacture. Indeed, bulky conduit assemblies requiring even a mereadditional square foot can be cost prohibitive in the valuable realestate of clean room environments, where the cost to build per squarefoot is especially expensive.

Moreover, repairing a faulty weld or replacing a flow device componentoften necessitates disassembly of a substantial portion of the liquiddelivery system. This also increases the down time of the processincorporating the component. For example, there is shown in FIG. 1, atypical prior art liquid delivery system 5. Liquid delivery system 5utilizes a conduit assembly 7 which employs a plurality of conduitsections 10, high integrity welds (not shown) and flow devices 12 fordelivering high purity liquid streams from system 5. Flow devices 12 canbe any device known in the art for processing a fluid, but typicallyinclude flow controllers, valves, filters and pressure transducers. Asshown in FIG. 1, conduit based system 7 requires a large degree ofavailable area inside the cabinet of liquid delivery system 5. Thus, inthe case where a particularly hard to reach component or weld requiresmaintenance and/or replacement, a significant portion of system 7 wouldneed to be disassembled. As can be appreciated, conduit system 7 iscomplex and costly to assemble and operate. For example, conduit system7 has a higher overall resistance to fluid flow than lesser complexsystems, thus an increased “down time” is required to purge the systemof fluids where necessary.

To provide a precise volume of fluid to a processing application, fluiddelivery systems may comprise a flow controller. Typically, flowcontrollers couple a sensor for measuring flow volume with a valve foradjusting flow volume. Measuring the flow volume of an entire fluidstream, however, can lead to long response time. Some flow controllersemploy a fluid bypass, measuring the flow volume of a small portion ofthe flow and inferring the flow volume in the bypass. These flowcontrollers, however, employ methods for maintaining the necessarypressure differential that are expensive, have high part counts that addtolerances and cost, or are difficult to manufacture yielding inadequateaccuracy or repeatability. Examples of such bypass flow controllersinclude those using a bundle of tubes or a sintered metal slug.

Additionally, atomizing and/or vaporizing a liquid in a gas stream isoften necessary in high purity fluid processing applications. Forexample, these processes may be employed to deposit high-purity, metaloxide films on a substrate. Moreover, the liquid mixtures may also beutilized for spray coating, spin coating and sol-gel deposition ofmaterials. In particular, chemical vapor deposition (CVD) is anincreasingly utilized high purity fluid delivery process for formingsolid materials, such as coatings or powders by way of reactants in avapor phase. Typically, a reactant vapor is created by heating a liquidto an appropriate temperature and bubbling a flow of carrier gas throughthe liquid (i.e. high purity fluid stream) to transport the vapor into aCVD chamber. Specifically, a gas stream and liquid stream are introducedinto a single channel or conduit at a T-junction. The CVD system pumps afluid stream at a steady, controlled rate into a hot region which mayinclude ultrasonic energy for effecting the mixture components. However,this technique creates a dead volume of material upon discontinuance ofthe process. Further, bubbling can often be an unpredictable method ofvaporization, in which the precise quantity of the liquid reactant isdifficult to control.

Accordingly, there is a need for an atomizer which predictably atomizesa fluid while eliminating dead volume upon discontinuance of theatomization process. Also, there is a need for an accurate, reliable andinexpensive flow controller. Similarly, there is a need for anintegrated liquid delivery system wherein the system schematic can beconsolidated to a single modular manifold device.

SUMMARY OF THE INVENTION

The present invention provides a flow controller used to adjust theliquid mass flowing through it to achieve a control voltage associatedwith the temperature difference equal to an external set-pointcorresponding to a desired mass flow rate. A portion of the fluid flowthrough the flow controller is diverted through a sensor channel. Heatis applied to the fluid stream in the sensor channel and the temperaturedifference between a point upstream and a point downstream of the heatsource is used to control a flow control valve. The sensor channelextends from a seamless slot carrying most of the fluid stream to anelevation lower than the elevation of the seamless slot.

It is to be understood that both the foregoing general description ofthe invention and the following detailed description are exemplary, butare not restrictive, of the invention.

BRIEF DESCRIPTION OF THE DRAWING

The invention is best understood from the following detailed descriptionwhen read in conjunction with the accompanying drawing. Accordingly, thepresent invention will now be described by way of non-limiting exampleswith references to the attached drawing, in which:

FIG. 1 is a perspective view of a prior art Fluid Delivery System;

FIG. 2 is a perspective view of the manifolded fluid delivery system inaccordance with one embodiment of the present invention;

FIG. 3 is an exploded view of the manifold assembly of the fluiddelivery system in accordance with FIG. 2;

FIG. 4 is a perspective view of the manifold assembly of FIG. 3 showingseamless slots in phantom;

FIG. 5 is a sectional view of the manifolded fluid delivery system ofFIGS. 1-4 taken along lines 3—3 of FIG. 3;

FIG. 6A is an enlarged view of the area designated by reference numeral27 of FIG. 4;

FIG. 6B is a sectional view taken along lines 6B of FIG. 6A;

FIG. 7 is a system schematic of the manifolded fluid delivery system ofFIG. 2;

FIG. 8 is a bottom exploded view of the manifold assembly of amultilayered manifolded fluid delivery system in accordance with oneembodiment of the present invention;

FIG. 9 is a longitudinal sectional view of a flow controller for use inan integrated fluid delivery system according to one embodiment of thepresent invention;

FIG. 10A is an exploded perspective view of a sub-assembly of the flowcontroller of FIG. 9;

FIG. 10B is an exploded perspective view of a sensor channel for theflow controller of FIG. 9;

FIG. 11 is a system schematic of the embodiment of the present inventionshown in FIG. 9;

FIG. 12 is a top view of a mixing slot of an atomizer in accordance withan embodiment of the present invention;

FIG. 13 is an exploded view of an atomizer/vaporizer in accordance withan exemplary embodiment of the present invention; and

FIG. 14 is a heat exchanger for use in an integrated fluid deliverysystem in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain terminology used in the following description is for convenienceonly and is not limiting. The words “right,” “left,” “lower,” and“upper” designate directions in the drawings to which reference is made.The words “inwardly” and “outwardly” refer to directions toward and awayfrom, respectively, the geometric center of the liquid delivery systemand manifold in accordance with the present invention and designatedparts thereof. The terminology includes the words noted above as well asderivatives thereof and words of similar import. The term “seamless” isgenerally defined as designating a continuous slot surface connectingcorresponding manifold apertures.

I. Single Sided Manifold

In accordance with the present invention, an integrated fluid deliverysystem (IFDS) is provided to dispense fluid streams. In an exemplaryembodiment, the fluid streams are of high purity. The high purity fluidstreams are typically utilized to manufacture semiconductor devices andtypically process such fluids as silicon, boron and phosphorousprecursors for delivery to a processing destination, such as a waferprocessing chamber. Those skilled in the art will recognize, however,that the present invention is applicable to any number of fluid streamchemistry and/or manufacturing environments.

Referring now to the figures in detail, wherein like numerals indicatelike elements throughout, there is shown in FIGS. 2-6B, a manifoldedfluid delivery system 15 in accordance with the present invention. Fluiddelivery system 15 includes a first modular manifold or “base” 16 forinternally channeling the high purity fluid streams along seamlessintegrated slots 18 (shown best in FIG. 3) formed therein.

As shown in the exemplary embodiment, base 16 is a substantially planar,rectangular substrate or plate having first and second surfaces 20 and22, respectively. Other shapes of base 16 can be used depending on theapplication. In an exemplary embodiment, base 16 is formed of stainlesssteel type 316LVAR (low carbon vacuum arc re-melt) selected for its highcorrosion resistance. Other materials suitable for the fluids used in aparticular application will be understood by those skilled in the art.The thickness of base 16 is suitable to the application and/or volume ofchemicals to be processed therethrough.

One or more flow/processing devices 12 are mounted on respectiveinterconnects 24. Interconnects 24 are mounted to base 16 via a mountingmeans, such as bolts (not shown), that are positioned through mountingholes 26. In an exemplary embodiment, mounting bolts are bolted tothreaded interconnect apertures 28. In an exemplary embodiment,interconnects 24 are removable to allow for repair, maintenance,replacement or redesign of the IFDS and/or its component parts.

As shown in FIG. 3 and FIG. 4, base 16 includes at least one, andtypically a plurality of seamless slots 18 (i.e., integrated seamlessslots), interconnect apertures 28 (FIG. 4), and slot porting apertures30 (FIG. 4) that are all formed on at least one of two major surfaces orfaces thereof. In an exemplary embodiment, slot porting apertures 30 aremetallic sealed. Other materials may be suitable for the seals,depending upon the application. Interconnect apertures 28 which may bethreaded are arranged in a flow device footprint adapted for receivingan interconnect for mounting a corresponding flow device 12. One or bothof first and second surfaces 20 and 22 can include seamless slots 18.

Seamless slots 18 are provided to consolidate a system schematic, suchas shown in FIG. 7 onto surfaces 20 and/or 22 of base 16 for providing amodular manifold component. The depth of slots 18 is suitable to theapplication and/or volume of chemicals to be processed therethrough. Inan exemplary embodiment, the system schematic is confined to a firstsurface 20 and seamless slots 18 are generally substantially ellipticalin cross section. In another exemplary embodiment, seamless slots 18 areconical in cross section truncated with a tangential rounded radius asshown in FIG. 5.

Seamless slots 18 may be chemically etched and polished to avoidparticulate entrapment. In an exemplary embodiment, seamless slots 18are polished down to less than 16 rms for removing the grain structureof the metal surface of base 16. The metal surface of base 16 can bepolished by extruding a polymer loaded with abrasives through base 16 ata high pressure through the use of polyurethane mill tooling. The uniqueshape of slots 18 is designed to complement the tooling for finishingpurposes. Rectangular slots diminish the polishing ability of the milltooling as rectangular slots have sharp corners that are difficult toaccess. Alternatively, seamless slots 18 may be formed by machining orother methods known in the art.

As shown in FIG. 4, seamless slots 18 include, along surfaces thereof,first slot porting apertures 30 extending from a surface of seamlessslots 18 through to another base surface (22 in FIG. 4), for channelinghigh purity fluid streams therethrough.

As shown best in FIGS. 5, 6A, and 6B slot porting apertures 30 arefinished with a detail 32 or “counterbore” to receive acorrosion-resistant seal. A corrosion-resistant seal such as a z-seal orc-seal, is used (in an exemplary embodiment, but not shown) uponconnection of a corresponding flow device 12 or pneumatic control line.Corrosion-resistant seals, as used in an exemplary embodiment, require ahigher tolerance finish (i.e., less than 16 rms) than that used forelastomeric fittings. The specifics of machining the appropriate finishfor receiving the selected commercially available seal is understood bythose skilled in the art. In some applications, it may be possible touse non-metallic, corrosion-resistant seals.

As shown in FIGS. 2 and 3, interconnects 24 are provided between bothslot porting apertures 30 and a desired flow device 12. Interconnects 34which may be attached to a low leakage fitting 36 (such as a VCR fittingmanufactured by Swagelok Company of Solon, Ohio) as a single piece, arealso provided between porting apertures 30 and desired flow device 12.Interconnect 34 is mounted to base 16 via mounting apertures 38 (boltsnot shown). Interconnects 24 are typically commercially availablefittings such as those manufactured by Swagelok Company of Solon, Ohiohaving a detail corresponding to that of apertures 30 for seating thecorrosion-resistant seal. Base 16 receives interconnects 24 by way ofbolting through interconnect apertures 28. In an exemplary embodiment, acommercially available corrosion-resistant seal (not shown) isconstructed of nickel and is interposed between apertures 30 andinterconnect 24 for forming a compression fitting. The material of theseal should be a softer metal with respect to base 16 so that uponseating interconnect 24 on base 16 the seal is compressed and deforms toseal the connection upon bolting or other securing means.

A face plate 40 is shown in FIG. 3, having a first and second surface.Face plate 40 is sealed or joined to first surface 20 of base 16 forenclosing seamless slots 18. Face plate 40 can be sealed to either firstor second surface 20 or 22 of base 16 depending upon the application. Abrazing medium 42 is disposed between base 16 and faceplate 40 and isutilized to seal face plate 40 to a desired surface of base 16 bybrazing. In an exemplary embodiment, a nickel brazing medium 42 is usedfor the brazing process and base 16 is secured to face plate 40 byvacuum brazing. In this way, face plate 40 is joined with base 16, sothat a first surface of face plate 40 abuts a surface (such as firstsurface 20) of base 16.

Face plate 40 may additionally include corrosion-resistant sealed plateporting apertures 44 positioned to overlay slots 18 of base 16. In suchan embodiment seamless slots 18 can be accessed by a processingdestination such as a wafer processing chamber through or from flowdevice 12. Plate porting apertures 44 are likewise finished with adetail 32 (as shown in slot porting apertures 30 in FIGS. 6A and 6B) or“counterbore” to receive a corrosion-resistant seal (such as a z-seal orc-seal, not shown) upon connection of a corresponding flow device orpneumatic control line to introduce the fluid streams to base 16. Thepresent invention can be practiced without employing corrosion-resistantsealed plate porting apertures 44. Moreover, the thickness of face plate40 is a matter of design choice for maintaining non-deformity whensecuring instrumentation to any resident plate porting apertures 44.

In an exemplary operation, base 16 receives each of the high purityfluid streams at a corresponding corrosion-resistant sealed slot portingaperture 30 for transporting a fluid along seamless slots 18.Corrosion-resistant sealed porting apertures 30 receive, upon connectionof a corresponding flow device or pneumatic control line or the like,fluid streams for transport of one or more fluids through seamless slots18 of base 16.

Slot porting apertures 30 are in fluidic communication with additionalslot porting apertures located along seamless slots 18, as well as plateporting apertures 44 for channeling high purity fluid streams betweenslots in different bases. In embodiments where face plate 40 may notemploy plate porting apertures 44, fluid would flow along seamless slots18 between corresponding slot porting apertures 30. Once mated to aninterconnect fitting 24, fluid device 12 is in fluidic communicationwith a corresponding one of the high purity liquid streams of base 16.

As shown in FIG. 7, an entire system schematic can be consolidated tobase 16 with the corresponding valving and flow devices interconnectedthereto for eliminating the need for the bulky conduit assemblies of theprior art. In this way, base 16 provides a modular system schematic fordispensing the fluid streams from integrated fluid delivery system 15 toprocessing destination such as a wafer processing chamber or otherdevice requiring fluid streams.

II. Multisided Manifold

In a further embodiment, a second base 16B is provided as shown in FIG.8 having similar details as base 16. The features of second base 16B areidentified by a reference numeral followed by the letter “B”. Secondbase 16B also has a first and second surface 20B and 22B respectively.Second base 16B also includes integrated seamless slots 18B formedthereon for channeling a fluid stream therethrough. Second seamlessslots 18B include, along surfaces thereof, second slot porting apertures(not shown) which are corrosion-resistant sealed porting aperturesextending from the surfaces of the second slots 18B through the secondbase 16B. Second base 16B is sealed to an available side of face plate40 in the same manner as that of the embodiment shown in FIG. 3. Plateporting apertures 44 overlay the slot porting apertures of theintegrated slots 18B and the faceplate is interposed between first base16 and second base 16B so that interconnect apertures 28 and 28B are inalignment.

In an exemplary embodiment, slot porting apertures in second base plate16B are in fluidic communication with slot porting apertures 30 whichare also through first slots 18 and second slots 18B for channelingfluid streams therebetween.

A second face plate (not shown) is connected to first surface 20B ofbase 16B for sealing slots 18B. It will be understood by those skilledin the art that any number of base sections 16 can be layered in thismanner depending upon the particular application and that the inventiondescribed herein is not limited to the illustration but used above forexplanatory purposes only.

III. Liquid Mass Flow Controller

Referring now to FIGS. 9-11, an exemplary embodiment of the presentinvention is shown in which base 16C is interconnected with a flowprocessing device to form a flow controller 46.

As shown in FIG. 9, a liquid flow controller assembly 46 employs a base16C and an interconnect plate 48. In an exemplary embodiment, base 16Cincludes a seamless slot 18C (best shown in FIG. 9) between base 16C andinterconnect plate 48. As above, with respect to base 16, base 16C andinterconnect plate 48 are joined together by a brazing medium 42 using avacuum brazing process. In an exemplary embodiment, base 16C can bevacuum brazed, at slot face 20C directly to second face 45 (shown inFIG. 10A) of interconnect plate 48 of liquid flow controller assembly46. Seamless slots 18C may be formed by machining, etching, or otherprocesses known in the art. Base may be a plate (or slot plate) havingtwo opposing surfaces or faces, one of these faces being slot face 20C.In this way, slot face 20C and second face 45 abut so that seamless slot18C is sealed by the abutment.

Porting apertures 50 are formed within interconnect plate 48 positionedto align with seamless slot 18C and extending to the first face 43 ofinterconnect plate 48 to allow the flow of liquid into and out of, aformed sensor channel 52 (discussed below). In an exemplary embodiment,porting apertures 50 are corrosion-resistant sealed similar to thosecorrosion-resistant sealed apertures previously discussed herein.Porting apertures 50 may provide for a portion of the liquid stream toflow into and through the sensor channel of the flow controller. Assuch, porting apertures 50 may be finished with a detail 32 or“counterbore.” Detail 32 is provided for receiving a corrosion-resistantseal (such as a z-seal or c-seal not shown) upon connection of acorresponding flow device or pneumatic control line to introduce oroutlet, fluid streams between base 16C.

Flow controller 46 includes a sensor channel 52 (best shown in FIG. 9)for providing a pathway for a fluid stream of base 16C. Sensor channel52 in sensor area 56 carries a portion of the fluid stream transportedinto base 16C, with the remainder to be carried along seamless slot 18C.Sensor channel 52 is provided for measuring a change in temperature ortemperature gradient (ΔT) of the portion of fluid flowing therein acrosspoints A and B in FIG. 11.

Sensor channel 52, as shown in FIGS. 9 and 10B, comprises a tube sectionin fluid communication with seamless slot 18C through porting apertures50 in interconnect plate 48. In a preferred embodiment of the presentinvention, sensor channel 52 extend downwardly from seamless slot 18Cthrough a sensor plate 49 and into a sensor area 56 of a sensor housing61, such that sensor channel 52 is at a lower elevation than seamlessslot 18C. Two temperature sensors 57 are mounted on sensor channel 52with a heater 59 is mounted on the sensor channel between thetemperature sensors. In an exemplary embodiment, the sensors and heatercomprise wire windings wrapped about the tubing. The heater transfersheat to the fluid to raise the fluid temperature up to 30 degreesCelsius. In an exemplary embodiment, however, the fluid temperature israised about 5 degrees Celsius to avoid degradation of certainprecursors that may be used with flow controller 46. In an exemplaryembodiment, the sensor channel 52 extends downwardly to reduce blockageof the sensor channel by gas bubbles carried in the fluid stream.

In an exemplary embodiment of the invention, buttons 53 are welded tothe ends of sensor channel 52. Buttons 53 are positioned in counterboresin sensor plate 49, and corrosion-resistant seals are compressed betweenbuttons 53 and interconnect plate 48. Spacers 55 may be positionedinside the corrosion-resistant seals. Then sensor plate 49 is fastenedto interconnect plate 48, such as with bolts, and sensor housing 61 isfastened to sensor plate 49.

Slot porting aperture 51 is formed in seamless slot 18C, extendingthrough base 16C and providing fluid communication between seamless slot18C and flow control valve 54. Flow control valve 54 is operablyconnected to temperature sensors 57. The temperature difference (ΔT)infers the flow through seamless slot 18C, and this temperaturedifference is used to generate an output signal voltage. The flowcontroller 46 can be used to adjust the mass flow through the flowcontroller 46 by adjusting the opening of flow control valve 54. Controlelectronics adjust the opening of flow control valve 54 until the outputsignal voltage is equal to a predetermined set-point in the controlelectronics corresponding to a desired mass flow rate. In an exemplaryembodiment, the set-point is determined by a variable resistor, such asa potentiometer. Flow control valve 54 may be a suitable valve for theparticular application that can be electronically adjusted to provide avariable flow rate. In an exemplary embodiment, flow control valve 54 isa piezotranslator, in which stacked ceramic disks press against aflexible metal diaphragm to open or close the diaphragm againstapertures in a fluid pathway. The pressure applied by the ceramic disksis proportional to a voltage applied to them. The flow rate isdetermined by the gap between the diaphragm and the flat surface havingthe apertures in it (up to about 0.002 inches in an exemplary flowcontrol valve).

Referring more particularly to FIG. 11, a system schematic of base 16Cand flow controller 46 is shown. Inlet 58 into base 16C is a highpressure inlet which branches into two separate pathways. The firstpathway is seamless slot 18C for providing a bypass pathway or channel.The second pathway is sensor channel 52. Flow valve 54 is in fluidiccommunication with seamless slot 18C for receiving the portion of fluidflowing through sensor channel 52 (which is proportional to the flowthrough seamless slot 18C) and the portion of fluid flowing throughseamless slot 18C. Seamless slot 18C provides a pressure drop frompoints 1 to 2 in FIG. 11. Sensor channel 52 and seamless slot 18C are influidic communication with a low pressure outlet 60, through controlvalve 54.

The change in temperature across points A and B of sensor channel 52corresponds to an actual fluid flow through the flow controller 46 andhas a very low response time on the order of 3 seconds or less. This isan improvement over the simple sampling of a single fluid stream as suchan arrangement yields very slow response time (e.g., 20 seconds). Thisarrangement provides a fast and accurate reading of fluid flow. Thismass flow controller can be a modular component for use in an IFDS.

IV. Atomizer

In accordance with another exemplary embodiment of the presentinvention, an atomizer for combining separate gas and liquid streams isprovided. This atomizer can be a modular component for use in an IFDS. Amixing point is defined by the junction of a liquid inlet to a mixingslot. A gas stream inlet is in fluidic communication with a side of themixing slot. A mixture outlet defines the remaining side of the mixingslot. A gas stream flowing into the mixing point is accelerated to ahigh velocity, reducing pressure for drawing the liquid into the gasstream by venturi effect.

There is shown in FIG. 12 a mixing slot 62 of an atomizer 64 forcombining separate gas and liquid streams. Mixing slot 62 has a mixingpoint 66 for atomizing a liquid stream into a gas stream. A stream ofthe high purity mixture of fluid and gas are utilized, for example, todeposit high-purity, metal oxide films on a substrate in processes suchas semiconductor manufacturing. Moreover, the liquid and gas mixturesmay also be utilized for spray coating, spin coating and sol-geldeposition of materials. Those skilled in the art will recognize,however, that the present invention is applicable to any number offluid/gas stream chemistry and/or manufacturing environments.

Atomizer 64 includes a base member 16D having a mixing slot 62 formed ina face thereof for producing a venturi effect at a mixing point 66. Inthe exemplary embodiment shown, base 16D is a substantially planar,rectangular substrate formed of type 316 stainless steel (low carbonvacuum arc re-milled) LVAR selected for its high corrosion resistance.Other shapes of base 16D can be used depending on the application, andother materials suitable for the fluids/gases used in a particularapplication may be used as will be understood by those skilled in theart. The thickness of base 16D is suitable to the application and/orvolume of chemicals to be processed therethrough. An exemplary basemember structure is shown in FIG. 12 and described below. Mixing slot 62may be formed by machining, etching, or other processes known in theart.

Mixing slot 62 of base member 16D has a gas input side 82 and a mixtureside 88. In an exemplary embodiment, mixing slot 62 is generallyhourglass shaped. Gas input side 82 and mixture side 88 are eachsubstantially triangular in shape and are in fluid communication througha throat joining their respective apices. A mixing point 66 is locatedat the throat of the hourglass shape. The venturi effect is caused bythe narrowing of the gas input side 82 and mixture side 88 of thehourglass shape, which increases the velocity of the gas lowering thepressure and drawing liquid into the gas stream. The particular fluiddynamics of the venturi effect will be understood by those skilled inthe art.

A liquid inlet 80 is in fluidic communication with mixing point 66 ofmixing slot 62. Mixing point 66 is defined by the junction of liquidinlet 80 and mixing slot 62. A gas stream inlet 84 is in fluidiccommunication with gas input side 82 of mixing slot 62. A valve (notshown) proximate to mixing point 66 may be provided for controlling theintroduction of a liquid stream through liquid inlet 80 and eliminatingdead volume upon discontinuance of the process as it controls the entryof the liquid stream at mixing point 66. A mixture outlet 90 is influidic communication with mixture output side 88 of mixing slot 62. Aface plate 40D abuts base member 16D sealing mixing slot 62.

The atomizer described herein may be provided as a modular component foruse in an IFDS.

V. Atomizer/Vaporizer

In one exemplary embodiment, as shown in FIG. 13, a mixing slot foratomizing a liquid into a gas stream, and a mixture heating slot forvaporizing the atomized liquid in the mixture are combined to form avaporizer 64E. A base member 16E has a mixing slot 62, as describedabove, formed in one of its faces for producing a venturi effect at amixing point 66. A gas slot 70 and a mixture heating slot 72 are formedin base member 16E in fluid communication with the gas input side 82 andmixture side 88, respectively, of mixing slot 62. Base member 16Einternally channels gas and fluid streams along seamless slots 70 and72. In the exemplary embodiment shown, base 16E is a substantiallyplanar, rectangular substrate having first and second surfaces 74 and78, respectively. Other shapes of base 16E can be used depending on theapplication. In this exemplary embodiment, base 16E is formed ofstainless steel type 316 LVAR (low carbon vacuum arc re-milled) selectedfor its high corrosion resistance. Other materials suitable for thefluids/gases used in a particular application will be understood bythose skilled in the art. The thickness of base 16E is suitable to theapplication and/or volume of chemicals to be processed therethrough.

In an exemplary embodiment, gas slot 70 is provided having a gas inletside 84 and a gas outlet side 86. Gas outlet side 86 of gas slot 70 isconnected to gas input side 82 of mixing slot 62. In an exemplaryembodiment, as shown in FIG. 13, gas slot 70 is a serpentine pathway forheating the gas stream to either a predetermined or adjustabletemperature. The degree of heating is dependent upon the length of thepathway and type of gas, as well as other factors (e.g., gas velocityand temperature difference between gas and base). The gas stream flowinginto a mixing slot may be heated to reduce the heat required to be addedto the mixture stream for vaporization.

FIG. 13 shows mixture heating slot 72 in fluidic communication withmixture side 88 of mixing slot 62. Mixture heating slot 72 has a mixtureinlet 90 and a mixture outlet 92. Mixture heating slot 72 is connectedto mixture side 88 of mixing slot 62. In operation a gas stream flowsthrough gas slot 70, into mixing slot 62, and then to mixing point 66.The velocity of the gas stream is increased in velocity by the narrowingof gas input side 82 lowering the pressure at mixing slot 62 andgenerating a venturi effect. In this way, portions of the liquid streamare drawn into the gas stream to provide an atomized mixture of gas andliquid streams to mixture heating slot 72. The mixture stream is heatedin mixture heating slot 72, vaporizing the atomized liquid in themixture to form a vapor mixture which exits base 16E via outlet 92.

As shown in FIG. 13, gas slot 70 and mixture heating slot 72 are sealedwithin base 16E by a pair of faceplates 40. A brazing medium (not shown)may be utilized to seal face plates 40 to surfaces 74 and 78 of base 16Eby brazing. In an exemplary embodiment, the brazing process is similarto the brazing process described herein. In an exemplary embodiment, anickel medium is used for the brazing process and base 16E is secured toface plates 40 by vacuum brazing. Alternatively, faceplates 40 may besealed to the base 16E by way of interconnect apertures 98 provided toreceive bolts (not shown). Additionally face plates 40 may includeporting apertures 100 for importing and exporting fluid and/or gasstreams directly to base 16E, such as from a flow control valve (notshown). Porting apertures 100 are sealed with a corrosion-resistant sealin an exemplary embodiment. While vaporizer 64E is shown having aserpentine layout, it is recognized by those skilled in the art that gasslot 70 and mixture heating slot 72 may be any number of layouts forheating the gas and mixture, or be essentially straight where necessary.

VI. Vaporizer

In an exemplary embodiment of a vaporizer, a heat exchanger is providedin fluidic communication with a mixture stream, such as at mixture side88 of mixing slot 62 of an atomizer as described above. The heatexchanger can encompass a single continuous pathway, such as mixtureheating slot 72, as shown in FIG. 13. The heat exchanger may be in fluidcommunication with the outlet of an atomizer as described herein. Theheat exchanger provides heat to an atomized liquid stream vaporizing theatomized liquid. Atomizing the liquid in a mixed stream of gas andliquid prior to vaporization lowers the temperature of vaporization,which may reduce degradation of certain liquid precursors.

The heat exchanger may be a serpentine pathway, as shown in FIG. 13, forheating the atomized mixture to a predetermined temperature forvaporization. The degree of heating is dependent, in part, upon thelength of the pathway and atomized chemistry. Other heat exchangerconfiguration, however, are possible and are within the scope of theinvention.

In another exemplary embodiment of the present invention, an alternateheat exchanger 94F, is shown in FIG. 14. Heat exchanger 94F may be usedto vaporize atomized liquid in a mixture stream produced by an atomizer64 or for vaporizing a liquid supplied to the inlet of heat exchanger94F which is neither atomized nor mixed with a gas stream. Heatexchanger 94F includes a base 16F with an inlet 102 in fluidcommunication with a mixture outlet of an atomizer or an unatomized andunmixed liquid stream. A distribution slot 104 formed in a slot face 106of base 16F is in fluid communication with inlet 102 and a plurality ofseamless slots 18F formed in slot face 106. A plurality of cross-slots108 are formed in face 106 intersecting the plurality of seamless slots18F. The cross-sectional area of the seamless slots is small enough toprevent surface tension from beading the liquid, which would reducecontact with the heated surface and reduce efficient heat transfer.Liquid is turned into vapor by the application of heat. If liquid isheated in a single slot or channel, bubbles of vapor can form that willexpand rapidly and push slugs of liquid to the outlet, causing spitting.The cross-slots allow vapor bubbles to find a path to the outlet withoutpushing a slug of liquid to the outlet. The cross-sectional area of thecross-slots 108 may be larger than the cross-sectional area of theseamless slots 18F to capture slugs of liquid and further reducespitting.

Although illustrated and described above with reference to certainspecific embodiments, the present invention is nevertheless not intendedto be limited to the details shown. Rather, various modifications may bemade in the details within the scope and range of equivalents of theclaims and without departing from the spirit of the invention.

What is claimed is:
 1. A flow controller for controlling a mass flowrate of a liquid flowing therethrough, comprising: a first channel fortransporting a mass of liquid therethrough; and a second channel influid communication with the first channel having a sensor for sensingmass flow rate therethrough; the second channel having a cross-sectionalarea operably smaller than the cross-sectional area of the firstchannel; the second channel extending from the first channel to anelevation lower than an elevation of the first channel.
 2. The device ofclaim 1 further comprising a heater and two temperature sensors on thesecond channel wherein the mass flow rate is determined by measuring athermal gradient between the two temperature sensors in the secondchannel due to heat applied by the heater.
 3. The device of claim 2further comprising a valve in fluid communication with the first channeland a control electronics having a pre-determined set-pointcorresponding to a desired mass flow rate, wherein the temperaturesensors generate an output signal voltage proportional to the thermalgradient and the control electronics adjust an opening in the valve tocontrol the mass flow through the flow controller so that the outputvoltage signal is equal to the set-point.
 4. The device of claim 1further comprising a base having a face and an interconnect platewherein the first fluid channel is a seamless slot formed in the face ofthe base and sealed by abutment with the interconnect plate.
 5. Thedevice of claim 4 wherein the second fluid channel comprises aperturesformed in a surface of the seamless slot.
 6. The device of claim 1further comprising a plurality of abutting plates, each having a firstand a second face wherein the first fluid channel is formed in one ofthe faces of one or more of a plurality of abutting plates to providerepeatable laminar flow among multiple flow controllers.
 7. The deviceof claim 6 wherein the first fluid channel is sealed by an abuttingplates.
 8. A flow controller for controlling a mass flow rate of aliquid flowing therethrough, comprising: a first fluid channel forcarrying a substantial portion of a liquid mass flow in fluidcommunication with a flow controller inlet, the first fluid channellocated at a first level; a valve for adjusting the mass flow ratethrough the flow controller, having a valve inlet in fluid communicationwith the first fluid channel and a valve outlet in fluid communicationwith a flow controller outlet; a sensor channel having a sensor inletand a sensor outlet in fluid communication with the first fluid channel,the sensor channel extending from the first fluid channel to a secondlevel located below the first level; two temperature sensors and aheater disposed on the sensor channel with the heater located betweenthe temperature sensors to create a thermal gradient between the twosensors proportional to the mass flow rate through the flow controller,the two temperature sensors for generating an output signal voltagecorresponding to the thermal gradient between the sensors; and a controlelectronics having a pre-determined set-point corresponding to a desiredmass flow rate, the control electronics for adjusting an opening in thevalve so that the output signal voltage equals the set-point.
 9. Thedevice of claim 8 wherein the first fluid channel is a seamless slotformed in an abutting face of a slot plate.
 10. The device of claim 8wherein the first fluid channel is a seamless slot formed by machining.11. The device of claim 9 wherein the sensor channel comprises a sensorinlet aperture and a sensor outlet aperture in fluid communication withthe first fluid channel.
 12. The device of claim 11 wherein the secondfluid channel further comprises tubing in fluid communication with thesensor inlet and sensor outlet apertures and the two temperature sensorsand the heater comprise windings on the tubing.
 13. The device of claim9 further comprising a valve inlet aperture and a valve seat, the valveinlet aperture being formed in the surface of the seamless slot,extending through the slot plate and the valve seat being formed in aface of the slot plate different from the face of the slot plate havingthe seamless slot therein.
 14. The device of claim 9 wherein theseamless slot is sealed by abutment of the slot plate to theinterconnect plate.
 15. An integrated fluid delivery system forproviding a precise stream of fluid, comprising: a first modularmanifold for internally channeling fluid along seamless slots formedtherein, the first modular manifold receiving one or more fluids atcorresponding sealed porting apertures thereof; and a flow controller influidic communication with the first modular manifold for preciselydispensing a liquid fluid stream from the first modular manifold of anintegrated fluid delivery system.
 16. The integrated fluid deliverysystem of claim 15 wherein the flow controller comprises a bypasschannel and a sensor channel, the bypass channel being a seamless slotin fluid communication with the manifold and formed in a base abuttingthe manifold, the sensor channel extending from the bypass channel, theseamless slot configured to provide a pressure drop across the sensorchannel.